Methods for electrically or thermally connecting electronics components onto, for example, a conductor or semiconductor substrate, are well known in the art. For example, both thermo-compression and solder bump bonding methods have been used to create connections between, illustratively, components in optoelectronic devices and/or microelectromechanical (MEMS) devices. FIG. 1 shows one illustrative method of forming a thermo-compression bond for use as a thermal or electrical interconnection. Specifically, in that FIGURE, component 110 has a layer of a material 120, typically gold, which is suitable for compression bonding. In order to bond component 110 with illustrative substrate 150, layer 120 on component 110 is, for example, lowered in direction 140 in a way such that it is brought into contact with a layer 130 of material, once again illustratively gold, on substrate 150. A sufficient temperature (e.g., 300 degrees Celsius) and pressure (e.g., 10 kgf/mm2 of gold area) are applied such that the gold layers deform and bond together. However, while such gold-gold thermo-compression bonding is useful in many regards, the temperatures and pressures required to create such a bond may damage sensitive electronic elements, such as transistors. As components become smaller and smaller (e.g., in MEMS devices), relatively high temperatures and pressures become more likely to cause damage to the increasingly fragile components.
FIG. 2 depicts another conventional method of thermally or electrically connecting two electronic components. Specifically, in that FIGURE, substrate 210 is, for example, a surface of an electronics chip such as a microprocessor in a MEMS package. Solder bumps 220 are created on the chip using well-known methods. In order to create an electrical or thermal connection between the chip and a substrate, such as a printed wire board, the solder bumps 220 are brought into contact with connection points and are then heated until they reflow. The bumps are then brought into contact with connection points on the exemplary printed wire board. Such solder bump methods are well-known as being very advantageous in forming electrical and thermal connections. However, once again, the temperature necessary to reflow the solder may damage components in the package. Additionally, solder bumps have been limited by certain design considerations. Specifically, such bumps must be above a certain size, typically larger than 20-25 microns in diameter, in order to achieve the desired bump height. Additionally, since it is undesirable to have solder bumps come into contact with one another when the solder is reflowed, solder bumps must typically be separated by a minimum distance, for example, 50 microns from the center of one bump to the center of an adjacent bump.
Finally, one other prior method for bonding two components together is to use a thermally and/or electrically conducting adhesive. However, such adhesives are typically subject to out-gassing as they cure, which may introduce damaging organic material on critical optical devices (e.g., lasers, detectors, etc.) and MEMS components that can interfere with proper performance of small components.
Embodiments of the present invention provide an improved bond and a method of manufacture therefore, whether it is thermal, electrical or otherwise, that substantially reduces the problems associated with the above-mentioned bonds.